Multi-axis manipulators are well-known in industry, and typically comprise multi-axis manipulators or robotic arms capable of being programmed to perform repetitive tasks. Such arms have many degrees of freedom, and may be fitted with tools of many different kinds to perform, for example, handling, welding, painting and so on.
Known manipulators of this kind are generally driven electrically, hydraulically or pneumatically, and are computer controlled.
Adjacent manipulator elements, for example at a major waist axis, elbow or wrist, are relatively movable about an axis of rotation, and suitable rolling element bearings are provided to resist axial and cantilever loads; such loads may be high in view of the potential reach of a manipulator and the forces capable of being exerted at the tool.
It has been proposed to use multi-axis manipulators in safety critical applications, in this case by way of example, for fairground and amusement park machinery, and in this application the manipulator carries a passenger carrying module or chair for one or more riders in place of a tool. Such machinery can offer far more flexibility as compared with bespoke fairground ride solutions, and moreover may offer a significantly enhanced degree of automation and integration with other amusement devices with increased reliability due to the use of standardized components. A multi-axis manipulator of this kind can also be programmed to give precisely controlled and variable motion dynamics within a defined envelope, and the ride may be changed on demand by use of a different program.
It will be understood that safety requirements for fairground and amusement park machinery are somewhat complex, and present the greatest challenge, and an absolute prerequisite is that riders are safe at all times. Accordingly the modes of potential machinery failure must be considered in detail, and to an extent which may not be necessary for an industrial device or robotic arm utilising conventional driveline components, bearings and structure whilst working in an environment from which humans are excluded.